3,194 research outputs found

    Mode identification for Balloon 090100001 using combined multicolour photometry and spectroscopy

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    In this paper, we show that method of mode identification using combined multicolour photometry and spectroscopy can be successfully applied to the pulsating subdwarf B star Balloon 090100001. The method constrains the spherical degree, l.We confirm that the dominant mode is radial and we show that for some other modes the method provides values of l consistent with the observed rotationally split triplet. Moreover, we derive a radius variation of 1.7 per cent for the dominant mode. The identification opens the possibility for constraining the internal structure of the star by means of seismic methods.Comment: MNRAS, in press, already at the online-early stag

    Time resolved spectroscopy of the multiperiodic pulsating subdwarf B star PG1605+072

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    We present results for the 2m spectroscopic part of the MultiSite Spectroscopic Telescope campaign, which took place in May/June 2002. In order to perform an asteroseismological analysis on the multiperiodic pulsating subdwarf B star PG 1605+072 we used over 150 hours of time resolved spectroscopy in order to search for and analyse line profile variations by using phase binning. We succeeded in finding variations in effective temperature and gravity for four modes. A pilot analysis using the \textit{BRUCE} and \textit{KYLIE} programs and assuming strong rotation and low inclination favours models with l=1l=1 or l=2l=2 with m≤0m\leq0.Comment: 2 pages, 2 figures, proceedings of the "Vienna Workshop on the Future of Asteroseismology", to appear in Communications in Asteroseismology v. 14

    Evidence for a planetary mass third body orbiting the binary star KIC 5095269

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    In this paper, we report the evidence for a planetary mass body orbiting the close binary star KIC 5095269. This detection arose from a search for eclipse timing variations among the more than 2,000 eclipsing binaries observed by Kepler. Light curve and periodic eclipse time variations have been analysed using Systemic and a custom Binary Eclipse Timings code based on the Transit Analysis Package which indicates a 7.70±0.08MJup7.70\pm0.08M_{Jup} object orbiting every 237.7±0.1d237.7\pm0.1d around a 1.2M⊙1.2M_\odot primary and 0.51M⊙0.51M_\odot secondary in an 18.6d orbit. A dynamical integration over 10710^7 years suggests a stable orbital configuration. Radial velocity observations are recommended to confirm the properties of the binary star components and the planetary mass of the companion.Comment: 8 pages, 7 figures, Accepted for publication in MNRA

    The MultiSite Spectroscopic Telescope campaign: 2m spectroscopy of the V361 Hya variable PG1605+072

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    We present results and analysis for the 2m spectroscopic part of the MultiSite Spectroscopic Telescope (MSST) campaign undertaken in May/June 2002. The goal of the project was to observe the pulsating subdwarf B star PG1605+072 simultaneously in velocity and photometry and to resolve as many of the >50 known modes as possible, which will allow a detailed asteroseismological analysis. We have obtained over 150 hours of spectroscopy, leading to an unprecedented noise level of only 207m/s. We report here the detection of 20 frequencies in velocity, with two more likely just below our detection threshold. In particular, we detect 6 linear combinations, making PG1605+072 only the second star known to show such frequencies in velocity. We investigate the phases of these combinations and their parent modes and find relationships between them that cannot be easily understood based on current theory. These observations, when combined with our simultaneous photometry, should allow asteroseismology of this most complicated of sdB pulsators.Comment: 9 pages, 5 figures, accepted for publication in A&A; Figure 1 at lower resolution than accepted versio

    The Gut Microbiota Composition in Dichorionic Triplet Sets Suggests a Role for Host Genetic Factors

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    peer-reviewedMonozygotic and dizygotic twin studies investigating the relative roles of host genetics and environmental factors in shaping gut microbiota composition have produced conflicting results. In this study, we investigated the gut microbiota composition of a healthy dichorionic triplet set. The dichorionic triplet set contained a pair of monozygotic twins and a fraternal sibling, with similar pre- and post-natal environmental conditions including feeding regime. V4 16S rRNA and rpoB amplicon pyrosequencing was employed to investigate microbiota composition, and the species and strain diversity of the culturable bifidobacterial population was also examined. At month 1, the monozygotic pair shared a similar microbiota distinct to the fraternal sibling. By month 12 however, the profile was more uniform between the three infants. Principal coordinate analysis (PCoA) of the microbiota composition revealed strong clustering of the monozygotic pair at month 1 and a separation of the fraternal infant. At months 2 and 3 the phylogenetic distance between the monozygotic pair and the fraternal sibling has greatly reduced and by month 12 the monozygotic pair no longer clustered separately from the fraternal infant. Pulse field gel electrophoresis (PFGE) analysis of the bifidobacterial population revealed a lack of strain diversity, with identical strains identified in all three infants at month 1 and 12. The microbiota of two antibiotic-treated dichorionic triplet sets was also investigated. Not surprisingly, in both triplet sets early life antibiotic administration appeared to be a major determinant of microbiota composition at month 1, irrespective of zygosity. By month 12, early antibiotic administration appeared to no longer exert such a strong influence on gut microbiota composition. We hypothesize that initially host genetics play a significant role in the composition of an individual’s gut microbiota, unless an antibiotic intervention is given, but by month 12 environmental factors are the major determinant.This study was performed as part of the INFANTMET project (10/RD/Infantmet/MFRC/705) and was funded by the Government of Ireland's Department of Agriculture Fisheries and in part by Alimentary Pharmabiotic Centre. KM is a Teagasc Walsh Fellow. CS, RPR and PWOT are members of The Alimentary Pharmabiotic Centre, which is a Centre for Science and Technology (CSET) funded by the Science Foundation Ireland (SFI), through the Irish Government’s National Development Plan (Grant no. 02/CE/B124 and 07/CE/B1368)

    Classifying faces by sex is more accurate with 3D shape information than with texture

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    Purpose: We compared quality of information available in 3D surface models versus texture maps for classifying human faces by sex. Methods: 3D surface models and texture maps from laser scans of 130 human heads (65 male, 65 female) were analyzed with separate principal components analyses (PCAs). Individual principal components (PCs) from the 3D head data characterized complex structural differences between male and female heads. Likewise, individual PCs in the texture analysis contrasted characteristically male vs. female texture patterns (e.g., presence/absence of facial hair shadowing). More formally, representing faces with only their projection coefficients onto the PCs, and varying the subspace from 1 to 50 dimensions, we trained a series of perceptrons to predict the sex of the faces using either the 3D or texture data. A "leave-one-out" technique was applied to measure the gen-eralizability of the perceptron's sex predictions. Results: While very good sex generalization performance was obtained for both representations, even with very low dimensional subspaces (e.g., 76.1 correct with only one 3D projection coefficient), the 3D data supported more accurate sex classification across nearly the entire range of subspaces tested. For texture, 93.8 correct sex generalization was achieved with a minimun subspace of 20 projection coefficients. For 3D data, 96.9 correct generalization was achieved with 17 projection coefficients. Conclusions: These data highlight the importance of considering the kinds of information available in different face representations with respect to the task demands
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